Propeller guard



Aug 2, 1932 a. c; MQEDEN y v PROPELLER GUARD Filed Nov. 1950 INVENTOR 551v 5/!400/A/ ATTORNEY BY I Patented Aug. 2, 1952.

untrue stares BEN O. MODIN, OF BROOKLYN, 'NEW YORK PROPELLER GUARD Application filed November 4, 1930. Serial No. 493,294.

The invention relates to guard means adapted forassociation with the screw proveller of a vessel for the purpose of protecting the same against fouling by free floating or submerged objects, such as driftwood and other floating debris.

It has for an object the provision of a relatively inexpensive guard which is adapted for ready application to propellers already installed, as well as being suitable for installation in the original construction of the vessel. A further obj ect of the invention resides in a guard member which is conveniently re movable for repair if damaged and replaceable in the case of destruction thereof.

A still further object of the invention re sides in a design and arrangement of the guard member relatively to the propeller which will not appreciably decrease its efficiency; and which, furthermore, will not tend to result in wedging of floating matter between it and the said propeller.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawing, in

which:

Fig. 1 is a side elevation of the stern of a vessel equipped with the novel guard memo" ber for its propeller. p

Fig. 2 is a fragmentary transverse section, taken on the line 22, Fig. l and looking in the direction of the arrows.

3 is an underneath view of the guard member.

Fig. 4 is a transverse section, on an enlarged scale, taken through a blade of the guard member.

Referring to the drawing, 10 designates the stern of a vessel and to the underside of which is mounted in the usual hangers or standard supporting struts 11 and 12 a propeller shaft 13 for rotating a screw propeller i l of the vessel and located in the usual manner forward of its rudder 15.

In accordance with the invention, the novel guard member is arranged to be mounted immediately forward of the propeller 1 1 and to be carried by the hanger 11. To this end, the guard members comprises an arcuate and supporting sleeve 16 adapted, for example, to fit over the propeller bearing 17 of the outer hanger 11, said sleeve being curved'to slightly more than a semi-circle for vertical support on the bearing and having a taper fit thereon. The said sleeve is further secured in position 65 by means of set screws 18 countersunk in the sleeve 16. i Three blades or fins extend radially outwardly from this sleeveand are integral thereh with so as to be rigid with the shaft bearing 17. Two of these blades 20 and 21 eXItend laterally from the said sle'evein opposite directions ina substantially horizontal plane which includes also the axis-f rotation of the propeller, while thethird blade 22 extends downwardly substantially at right angles to the plane of the blades and 21, thus being located midway between the same and in a vertical plane. V The aforesaid blades, moreover, are tapered '70 to stream-line proportions, that is to say, their respective forward edges '23 are rounded and broader than the after edges 24. By this expedient, substantially no dead space results in the region immediately forward of the propeller. and thus insures maximum' efficiency in the operation of the said propeller. Furthermore, both the edges. 23 and 24 are curved longitudinally, as indicated, to deflect and direct any material contacting therewith laterally outwardly therefrom or downwardly and from either above or below the propeller. Driftwood and the likewill therefore readily slide off the inclined edges of said blades, which are of substantially equal radius, with their tips 25 constructed to extend slightly beyond the circumference of the corresponding propeller blades, 1e so that the dbris will be directed also beyond saidl'propeller; w The after edge 2 L is preferably curved, also, and to a shorter radiusthan the edge 23 to increase space for better propeller action; and the tip 25 of the meeting edges ter- 5 Ininates substantially in the same plane with the, end 26, where the edge 24L merges into the sleeve, to afford ample clearance for the propeller. I I

It will be understood, of course, that the mo blades instead of being secured to a removable sleeve 16 may be formed integrally with the bearing or hub 17 of hanger ll if originally built into the boat. However, by utilizing a sleeve as set forth, it is a simple matter to remove or replace a guard member, the operation requiring only a very brief period, not exceeding as a rule fifteen minutes, and does not necessitate taking down the entire hanger.

It will be noted, because of the horizontally disposed blades 20 and 21 extending in opposite directions from the sleeve, that in case of partial submerging of the stern 10 these blades will act as a horizontal rudder to assist in lifting said stern; and, due to their slight thickness and stream-line contours,

will not. in passing through the water materially impede the progress of the vessel therein.

I'claim:

1. In a propeller-driven vessel; a guard for the propeller thereof, comprising an arcuate sleeve adapted-to be rigidly secured over the lower half of the propeller shaft I bearing immediately forward of the propeller and having a pair of integral stationary blades extending laterallytherefrom in opposite directions and substantially in a horizontal plane, and anintegral intermediate stationary blade extending downwardly therefromsubstantially in a vertical plane.

'2, In a propellerdriven vessel: a guard for the propeller thereof, comprising an arcuate sleeve adapted to be rigidly secured over the lower half of the propeller shaft bearing immediately forward of the propeller and having a pair of integral stationary blades extending laterally therefrom in oposite directions and substantially in a horizontal plane, and an integral intermediate stationary blade extending downwardly therefronrsubstantially in avertical plane,

andsthe said tips of all of the blades lying substantially in the same plane with the points atwhichthe inner ends of the respective after edges merge with the sleeve 3 In a propeller-driven vessel: a guard for the propeller thereof, comprising an arcuate sleeve adapted to be rigidly secured over the. lower half of the propeller shaft bearing immediately forward of the propellerand having a pair of integral stationary blades extending laterally therefrom in opposite directions and substantially in a horizontal plane, and an integral intermediate stationary blade extending downward- 1yi therefrom substantially in a vertical plane, t e forward and the after edges of all of the blades being curved, the curvature of the after edge being of a greater radius than the forward edge, and the said tips of all of the blades lying substantially in the same plane with the points at which the inner ends of the respective after edges merge with the sleeve.

4. In a propeller-driven vessel: a removableguard attachment for the propeller thereof, comprising a unitary structure adapted to be rigidly positioned with respect to the propeller shaft bearing and embodying a pair of stationary and horizontally disposed blades adapted when the attachment is secured to the said propeller shaft bearing to extend in opposite directions from its longitudinal axis in a horizontal plane including said axis, and an intermediate stationary blade extending then downwardly from said axisin a vertical plane including the axis, all of said blades projecting beyond the tips of the'guarded propeller.

In testimony whereof I afiix my signature.

BEN C. MODIN. 

